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DOI: 10.1103/vwm1-x3vw
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Ref Arxiv: 2503.15134
DOI: 10.1103/hl8q-4wy9
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Discrete time crystals (DTCs) are a nonequilibrium phase of matter characterized by the breaking of time-translation symmetry in periodically driven quantum systems. In this work, we present a detailed thermodynamic analysis of a DTC in a one-dimensional spin-1/2 chain coupled to a thermal bath. We derive a master equation from the microscopic model, and we explore key thermodynamic quantities, such as work, heat, and entropy production. Our results reveal that the DTC signature inevitably decays in the presence of environmental noise, but we show that a periodic measurement scheme can mitigate the effects of decoherence, stabilizing the subharmonic oscillations of the DTC for extended periods. These findings provide insights into the robustness of time-crystalline phases and potential strategies for protecting them in experimental settings.

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Ref Arxiv: 2509.21924
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The magnetic monopole of a dark sector has been advocated as an appealing dark matter candidate. We revisit the computation of the monopole abundance $Ω_M$, generated by a thermal phase transition in the minimal 't Hooft-Polyakov model. We explore the three regimes where the phase transition is second order, weakly first order, or supercooled, identifying the parameter space regions where $Ω_M$ can match the observed dark matter abundance. However, the dark sector necessarily contains a stable electrically-charged particle, namely a massive vector boson, with a calculable abundance $Ω_{W'}$. We show that, under minimal assumptions, $Ω_{W'}$ is always far larger than $Ω_M$: dark monopoles cannot constitute a sizeable fraction of dark matter.

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DOI: 10.1063/5.0271678
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There is a growing interest in the recent years toward developing wide gap semiconductor nanostructures, and a lot of efforts have been dedicated to ZnO. In order to design core shell structures, a larger bandgap material is needed, which would ideally be similarly environment friendly. ZnS is an interesting possibility and although some efforts were devoted to it in the literature, its properties are not yet fully understood and precisely measured. In this work, we make a thorough analysis of high quality ZnS epilayers, in order to precisely determine the basic optical properties related to excitons and impurities in ZnS. We have made the first precise quantitative determination of residual strain using high-resolution x-ray diffraction. This allows us to demonstrate that, as it was hypothesized in most previous works, thermoelastic strain originating from the layer-substrate expansion coefficient mismatch is responsible for shifts and splitting of exciton photoluminescence lines. The identification of the bound excitons’ optical transitions is analyzed through their temperature/power dependence, in order to precisely assess their exact nature. Combined with the careful determination of donor and acceptor ionization energies in our ZnS sample, we discard the possibility of sodium as the main residual acceptor, as it has often been proposed in the literature.

Ref HAL: hal-05295439_v1
DOI: 10.1116/6.0004707
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In this paper, we theoretically and experimentally investigate the specificities of single-walled carbon nanotubes (SWNTs) for field electron emission (FE) and field ion evaporation (FI). For FE, the small radii of curvature of these nanotubes lead to a significant widening of the tunnel barrier, and thus, for a given emission current, the fields at the surface of the SWNTs are significantly higher than commonly observed in standard large radius FE. For currents in the μA range, for example, fields ranging from 7–8 V/nm for large nanotubes to 17–18 V/nm for the thinnest are required. These strong fields, in turn, have repercussions on FI and electrostatic forces. The electric fields and longitudinal electrostatic forces during FE and FI as a function of nanotube radius are presented. The evolution of the nanotube during field evaporation was also studied in an environmental transmission electron microscope as a function of field strength and polarity. A strong dissymmetry between positive and negative polarity is observed. For negative polarity, the nanotubes can gradually shorten as the voltage is increased, whereas in positive polarity, they are almost systematically torn off before apex evaporation occurs. A model to explain this dissymmetry for our samples is presented. These results can be used to optimize nanotube cathode geometries.

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DOI: 10.1021/acs.macromol.4c03215
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Colloids are widely used as model systems to study the glass transition, with much research focused on hard or soft neutral colloids and their mixtures. However, the glass transition of soft-charged spherical colloids and its dynamic effects remain underexplored. This study assesses the glass transition of polymeric multiarm charged soft colloids using shear rheology, coarse-grained molecular dynamics (MD) simulations, and X-ray scattering. Strong particle-particle correlations, driven by electrostatic interarm repulsion, inhibit Newtonian behavior in the dilute regime. The liquid-to-glass transition occurs at just 0.25 wt %, marked by weak caging and minimal interdigitation of arms, as evidenced by particle contact analysis in MD simulations and the strong frequency dependence of the dynamic moduli. Particle shells interdigitate only well within the glassy regime, leading to a nearly frequency-independent rheological response. The weak volume fraction dependence of the yield stress sets these charged systems among the softest colloids reported in the literature.